title: Development of a spectrophotometric immuno-agglutination assay for quantitation of IgG for Escherichia coli O157.
abstract: A direct spectrophotometric immuno-agglutination assay for quantitation of specific Escherichia coli O157 IgG was developed. Initial linear rates of increase in absorbance at 550 nm as a result of agglutination were found to increase with both cell and antiserum concentrations. Optimum conditions consisted of 1 x 10(8) cells/ml, 40 degrees C, and 0.005 M phosphate buffer (PB) containing 0.05% NaCl and 0.02% sodium azide at pH 7.4. A completely linear increase in absorbance was obtained with affinity purified IgG under optimum conditions of the assay. The useful range of the assay was between 13 and 104 micrograms of O157 specific IgG per ml of reaction mixture.
authors.affiliation: Department of Food Science, Massachusetts Agricultural Experiment Station, University of Massachusetts, Amherst 01003, USA.
authors.forename: A
authors.initials: A
authors.lastname: Abolmaaty
authors.forename: R E
authors.initials: RE
authors.lastname: Levin
authors.forename: M A
authors.initials: MA
authors.lastname: Abdallah
mesh_terms: D000372:Agglutination Tests; D000818:Animals; D000907:Antibodies, Bacterial / Q000032:analysis*; D019453:Escherichia coli O157 / Q000276:immunology*; D005260:Female; D006863:Hydrogen-Ion Concentration; D007106:Immune Sera / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis*; D011817:Rabbits; D013053:Spectrophotometry; D013696:Temperature
chemical_list: D000907:Antibodies, Bacterial; D007106:Immune Sera; D007074:Immunoglobulin G